To evaluate the safety and immunogenicity of HIV-1 SF-2 recomb. p24 subunit vaccine when administered as part of prime-boost HIV-1 vaccination regimens employing ALVAC-HIV vCP205 with or without HIV-1 SF-2 rgp120 and to evaluate the safety and tolerabiltiy of HIV-1 SF-2p24 when administered with ALVAC-HIV vCP205 or when combined with HIV-1 SF-2 rgp120 administered simultaneously with ALVAC HIV-1 vCP205.